This invention, which is illustrated and described herein in a military setting wherein it offers special utility (though it is not per se dedicated to military use), relates to a layered jacket barrier structure which may be applied as an outside surface coating to an exposed container, such as the tanker container body in a large hydrocarbon fuel-supply truck, and a vehicle's exposed hydrocarbon fuel tank, to effect quick self-sealing against leakage from a container puncture wound, such as a penetrating bullet wound. We refer to this coating structure as being a barrier structure that disables a container-penetrating projectile, such as a bullet, from producing an uncontrolled liquid leak from the container. It also relates to methodology which is associated with this barrier coating structure.
For illustration purposes only, a preferred embodiment of the coating of the invention is specifically disclosed and illustrated herein in relation to the fuel tank in a smaller-than-tanker military vehicle.
Such a coating can effectively substantially nullify a combat tactic which involves (a) creating a penetrating bullet wound in such a tank/container, (b) thereby producing flammable fuel leakage typically enhanced by the usual positive residual pressure in that tank, (c) and then, using and firing an incendiary projectile, igniting the leaked fuel to attack the associated vehicle by fire.
The layered coating proposed by the present invention, which is also referred to herein as a projectile disabling barrier structure, employs two foundation materials, one of which, by itself, is employed as a singularity to form one type of the two different layer types, or structures, employed according to the invention, and the other of which is combined, as an entrained substance, in and with the first-mentioned foundation material to form the second layer type. The second layer type, which combines the two materials just generally mentioned, performs with behavior that effectively characterizes a de facto third “type” of material—in effect, a composite material.
Several different layered coating structures are illustrated and described herein, with the preferred coating structure being formed, as will shortly be described, as one including three cooperative layers.
According to practice of the invention, and in the mentioned, illustrative setting involving an exposed fuel tank in a military vehicle, the exposed surface of such a tank is appropriately coated/jacketed with a sandwiched, plural-layer, self-healing/self-sealing barrier structure which implements several important, cooperative mechanisms for mending a bullet-puncture fuel leak.
One of these mechanisms features significant elasticity furnished by elastic stretch and recovery of a very high-elastic-stretch-capable (about 400% elongation before breakage) elastomer. The elastomer employed to implement this mechanism is also a modest “reaction-time” substance which responds, in the setting now being described, to fuel contact with modest hydrocarbon fuel-imbibing and swelling actions. The term “modest” will be characterized herein shortly.
Another mechanism employs a layer-embedded pellet, or bead-like, fuel-imbiber material (also called a “reaction” substance) which responds aggressively and quickly to contact with the usual hydrocarbon fuel to undergo a rapid absorption (imbibing) of any leaking fuel, accompanied by a rapid, three-dimensional, physical, synergistic, swollen-volume enlargement (about 300%) because of such absorption. The term “synergistic” is used herein because of the fact that the swollen bead volume which develops as just mentioned appears to be greater than the sum of the individual volumes of the interacting fuel and the reaction-substance bead-like material.
Still a further mechanism involves the use per se of the mentioned bead-like material, which further responds to contact with hydrocarbon fuel in a manner which results in a congealing reaction occurring between absorbed fuel and the imbibing bead material. This congealing reaction can be likened to coagulation, with respect to which there results a tacky, thickened mass of material that tends to coalesce so as to form a very tenacious barrier continuum which contributes significantly to the blockage of outward flow and leakage of fuel from a tank.
Yet another mechanism at work in the sealing operation of the invention comes about because of tension which exists in an outer elastomeric material layer that forms part of the invention. This tension leads to enhanced compression of leakage-contact-swollen layer material in the vicinity of a container puncture wound.
The consequences of the above-mentioned mechanism actions and behaviors are that a leakage passage which results from a bullet (projectile) strike which penetrates the proposed layer-like barrier structure (a) is rapidly substantially fully closed almost immediately by the mentioned elastomer mechanism, (b) is additionally compression-sealed quickly by fuel-imbibing-produced material swelling and expansion resulting from material contact with leakage fuel, and (c) is further closed off by the coagulation/congealing action just mentioned.
These and other important mechanisms and features, soon to be more fully described, are provided by a unique, multi-layer jacket which includes, fundamentally, the above-mentioned, several, different, individual and composite materials which work in cooperation with one another in accordance with the invention. Among these other mechanisms and features are (a) that initial tension is built into the outer layer of a plural-layer structure fabricated in accordance with the invention, and (b), that the different layers preferably, though not necessarily, and as initially created, increase in thickness progressing outwardly through the layer structure from the surface of a protected fuel (or other) tank.
All of the features and operating mechanisms of the invention will be more fully understood and appreciated as the description which now follows is read in conjunction with the accompanying drawings.